[Bldg-sim] LEED - What does it take?
RobertWichert
robert at wichert.org
Mon Jan 21 07:33:43 PST 2013
Thanks Vikram,
Your thoughts are right on point and resonate with my instinctive
reaction too.
Cheers!
Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060
FAX +1 916 966 9068
===============================================
On 1/21/2013 6:43 AM, Sami, Vikram wrote:
>
> My two five cents -- adding to the many cents already thrown in the pot.
>
> ·LEED & Appendix G at this point are based on energy cost -- not raw
> BTUs or carbon. So the relative costs of your fuel mix will have an
> effect on final scores (in a place where electricity is cheap and
> heating fuel is not -- you are likely going to have less credit for
> your SEER rating). I don't agree with it, but that's how the system is
> set up.
>
> ·The effectiveness depends on your baseline energy usage. For example
> -- if you have a building that has very small HVAC component, even a
> 50% reduction won't get you to 10% overall.
>
> ·LEED addresses consumption and not efficiency (which is a good
> thing). So you get credit for 'driving less'. Hours that you don't
> need to run your HVAC = money in your pocket (the envelope leg of
> Nick's tripod analogy).
>
> ·It also depends on other factors like how you deliver the energy. For
> example -- using hydronic cooling & heating will likely save you more
> energy than an all air system with a higher EER on the chiller. Using
> a waterside economizer goes back to the 'driving less' analogy.
> Hydronic systems are also less prone to reheat (simultaneous heating &
> cooling) issues that you have with all air systems.
>
> The way I like to approach LEED projects is to go after the intent of
> the credits rather than the point -- you'll be surprised at how often
> you end up with a higher LEED score when you do.
>
> Apologies to Robert if this doesn't directly respond to the original
> question.
>
> **
>
> *Vikram Sami*, LEED AP BD+C
>
> Sustainable Design Analyst
>
> 1315 Peachtree St. NE, Atlanta, GA 30309
>
> t: 404-443-7462 f: 404.892.5823 e: vikram.sami at perkinswill.com
> www.perkinswill.com <http://www.perkinswill.com/>
>
> *Perkins+Will.*Ideas + buildings that honor the broader goals of society
>
> *From:*bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Nick Caton
> *Sent:* Wednesday, January 16, 2013 8:09 PM
> *To:* Dennis Knight; RobertWichert
> *Cc:* bldg-sim at lists.onebuilding.org; EnergyPro at yahoogroups.com
> *Subject:* Re: [Bldg-sim] LEED - What does it take?
>
> Man, every time I start a reply 3 more have come out, haha! I think
> we're all pretty much on the same page though =). This is largely
> written in response to Robert's most recent reply:
>
> Applying 10% improvement to lighting/mechanical equipment/envelope is
> merely a strategy for achieving performance figures in the right
> ballpark once energy modeling begins. No more and no less. I can
> attest this has worked well for me in the past, but I _never_ meant to
> imply "..and you're done."
>
> This is just a means of getting the ball rolling and ensuring the
> important decision makers understand they have a role to play.
>
> I agree completely regarding the limits of SEER and every other
> standardized efficiency rating I've worked with. Seasonal and steady
> state efficiencies are NEVER direct indicators of actual system
> consumptions, they are merely representations of performance under
> specific conditions. That said, they do have a useful time & place
> which occurs at the beginning of a project, before a more detailed
> analysis can be made with energy models or otherwise. SEER may or may
> not be an inadequate efficiency metric for your specific climate, but
> that doesn't change what defines your baseline equipment.
>
> If the goal is simply to reduce heating and cooling energy
> consumptions of your HVAC systems by XX%, and I can't build something
> resembling the final design for an energy model, I simply can't offer
> a better answer than "improve your heating and cooling efficiencies by
> XX%," recognizing this alone will not get you there if your lighting
> consumptions and envelope performance do not do their part.
>
> A black and white answer to what minimum performance is required of
> any system for any specific LEED project goal is truly unapproachable
> until you start the energy model that will determine the results ;).
>
> As it happens however, I can answer Robert's most recent hypothetical
> almost directly: I have performed a preliminary study for a building
> in the vicinity of El Paso, TX using 15 SEER AHU's with energy
> recovery. I determined a 30% LEED improvement would have been
> attainable using an envelope matching 90.1 baseline constructions, but
> this entailed a roughly 50% LPD reduction (I would have performed the
> lighting design and can attest this was achievable), and a healthy
> laundry list of EEM's for mechanical, with a heavy service hot water
> equipment load helping things along.
>
> So to wrap up, I'd say 15 SEER units absolutely can be one part of a
> bigger picture achieving a 10% LEED performance rating.
>
> Apologies for the walls of text... sometimes the quick & easy answer
> is "there aren't any quick and easy answers!" Hope this discussion is
> helpful to you and yours in any case!
>
> ~Nick
>
> cid:489575314 at 22072009-0ABB**
>
> **
>
> *NICK CATON, P.E.*
>
> SENIOR ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway, suite 200
>
> olathe, ks 66061
>
> direct 913.344.0036
>
> fax 913.345.0617
>
> www.smithboucher.com__
>
> *From:*Dennis Knight [mailto:dknight at wholebuildingsystems.com]
> *Sent:* Wednesday, January 16, 2013 6:24 PM
> *To:* RobertWichert
> *Cc:* Nick Caton; bldg-sim at lists.onebuilding.org;
> EnergyPro at yahoogroups.com
> *Subject:* Re: [Bldg-sim] LEED - What does it take?
>
> Robert,
>
> Simple answer is "No" - that is my point - it more than likely never
> will. You have to include all of your proposed energy conservation
> measures that you are likely to apply into a single model with your
> user and climate/local specific schedules and profiles included to see
> what the aggregated savings maybe. You can run multiple models
> changing only one component to do some sensitivity analysis to see
> what variables/measures may give you more dramatic changes in total
> energy consumption, cost, carbon emissions, indoor comfort, life
> cycle cost, life cycle assessment, etc. (which ever your client and
> you are using as your decision making criteria).
>
> As for the question regarding 10% energy reduction using 15 SEER
> equipment: I've gotten 10% better energy performance using 90.1
> minimum SEER compliant equipment and effecting change in lighting
> power density, lighting controls, controllable plug loads and better
> envelope/less infiltration, better ventilation and properly downsizing
> the mechanical systems. You do not always have to improve the
> mechanical efficiency of the HVAC equipment to achieve an energy
> efficiency improvement target. It is a whole building analysis that
> the owner's O&M behavior can have a major impact on. Conversely, I've
> had bleeding edge efficiency and complexity in the energy using
> systems at some facilities and the buildings perform worse than an
> minimum code compliant building or a local median EUI when a
> custodian who knows how to turn things off at night could have done
> better - when the owner does not understand how the design team
> intended the building to be operated when they made their analysis.
> For example, I just investigated a net zero energy house that was
> donated to an international non-profit. It has 22 SEER geothermal
> heat pumps, an envelope so tight it had no air measurable leakage at
> 80 pascals, LED lighting, solar water heater, energy recovery
> ventilator, solar PV, SIPS panel wall system, commercial grade low e
> windows and a sophisticated energy monitoring system. It is built
> right next to a conventionally built house, stick framed, minimum
> residential code compliant construction with 13 SEER air source heat
> pumps. Both are occupied by single mothers with two children. The
> net zero house has worse energy performance than the code minimum
> house almost entirely due to occupant behavior. I personally did not
> believe you could operate that house such that it would ever consume
> much energy, but you can. In this case the owner was not determined
> until after the house was constructed and did not have a stake in the
> design and was not trained on the special features of the house when
> it was offered to her. Now that she has been educated I can see some
> reductions - but the house is still falling way short of its goal of
> net zerobecause the owner is just unwilling to change her lifestyle no
> matter what the nergy costs are.
>
> Dennis
>
> On Wed, Jan 16, 2013 at 6:28 PM, RobertWichert <robert at wichert.org
> <mailto:robert at wichert.org>> wrote:
>
> I suppose the modeling software and how it treats energy might have
> something to do with it too (Note to CA and TDV), but for starters the
> modeling software will look at actual conditions in the particular
> place where the project is located. As an absurd case, if there was
> no cooling needed, an infinite SEER would show no improvement. SEER
> is for "typical" and each project is not necessarily typical. For
> somewhere with a high cooling demand, SEER should have a greater
> effect, but cooling is only a small part of the energy budget.
>
> I can appreciate that with "10% better walls, 10% better windows (or
> how about 10% less windows), 10% lower lighting wattages, 10% more
> efficient hot water, all compared to the standard, you could get 10%
> better using a SEER 14.3, but I have never gotten that result. I
> suppose that I need to look harder at the other legs on the stool.
> For me, I need SEER 17 to get to 10% better in California with a
> somewhat lopsided stool. I am curious what experience others have.
>
> The theoretical answer may be "Make everything else use 10% less
> energy than standard and have a SEER 14.3 AC unit, and you're done"
> but to be honest, that doesn't ever work for me.
>
> Maybe a better question is; have you ever gotten 10% better than
> ASHRAE 90.1 with a 15 SEER AC system? In a real project with real
> people fighting over costs, etc.?
>
>
>
> Robert Wichert P.Eng. LEED AP BD&C
> +1 916 966 9060 <tel:%2B1%20916%20966%209060>
> FAX+1 916 966 9068 <tel:%2B1%20916%20966%209068>
>
>
>
>
>
>
>
> ===============================================
>
> On 1/16/2013 2:25 PM, Dennis Knight wrote:
>
> Robert,
>
> SEER is a seasonal energy efficiency ratio and is unitless. It is
> the "cooling output during a typical cooling-season divided by the
> total electric energy input during the same period":
> http://en.wikipedia.org/wiki/Seasonal_energy_efficiency_ratio. A
> unit with 10% or better seasonal cooling energy efficiency over a
> 13 SEER unit would have a SEER rating of 14.3 or greater (1.1x13)
> if all other operating parameters were held constant. See link
> for definitions and other references.
>
> Dennis
>
> On Wed, Jan 16, 2013 at 5:11 PM, RobertWichert <robert at wichert.org
> <mailto:robert at wichert.org>> wrote:
>
> My current project has very good windows, "standard" walls, you're
> right about the lighting, it's right on budget (but residential
> doesn't really have a budget, so the small common areas are right
> on budget), better than standard roof.
>
> I absolutely agree with you, Nick, on achieving 10% better, but
> all the trades point to the others. It's kind of comical, actually.
>
> I guess my question on this list could be rephrased, using your
> approach, as "What SEER is 10% better than SEER 13?"
>
>
>
>
> Robert Wichert P.Eng. LEED AP BD&C
> +1 916 966 9060 <tel:%2B1%20916%20966%209060>
> FAX +1 916 966 9068 <tel:%2B1%20916%20966%209068>
>
>
>
>
>
>
>
> ===============================================
>
> On 1/16/2013 12:34 PM, Nick Caton wrote:
>
> A very simple way of looking at LEED & energy, which I come back
> to often for discussions on that level, is to consider a
> building's performance like a tripod with three important legs:
> Lights, Mechanical, and Envelope. If any of those legs is too
> short, the tripod falls over.
>
> Building on that analogy, to do 10% better than a LEED baseline, a
> good starting place is to have at least:
> - 10% better lighting (10% lower LPD),
> - 10% better HVAC & hot water heating (10% better efficiencies), and
> - 10% better envelope (10% more insulation in walls/roof, 10%
> better windows).
> For each of these, you can source the baseline/prescriptive levels
> from the standard of your choosing.
>
> Overperforming in one area can sometimes make up for
> underperfomance in another, but with diminishing returns. Amazing
> HVAC equipment/design has a harder time shining when you have a
> poor envelope and/or the lighting designer treats LPD's as a
> "budget" they have to use up. For such reasons, it's advisable to
> always consider building performance in holistic fashion in
> early/broader discussions.
>
> That's my (simple) take anyway!
>
> ~Nick
>
> NICK CATON, P.E.
> SENIOR ENGINEER
>
> Smith & Boucher Engineers
> 25501 west valley parkway, suite 200
> olathe, ks 66061
> direct 913.344.0036 <tel:913.344.0036>
> fax 913.345.0617 <tel:913.345.0617>
> www.smithboucher.com <http://www.smithboucher.com>
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>
> [mailto:bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>] On Behalf Of
> RobertWichert
> Sent: Wednesday, January 16, 2013 9:24 AM
> To: EnergyPro at yahoogroups.com <mailto:EnergyPro at yahoogroups.com>;
> bldg-sim at lists.onebuilding.org <mailto:bldg-sim at lists.onebuilding.org>
> Subject: [Bldg-sim] LEED - What does it take?
>
> I know that LEED is way more than just energy, and energy is way
> more than just equipment, but just for a basis, what SEER and EER
> do people have to use to get 10% better than ASHRAE 90.1 to
> qualify for LEED? I also know that you don't have to use ASHRAE
> 90.1, but that is what I am doing.
>
> So, what does it take?
>
> My shot - Residential Apartment, individual DX units, 17 SEER and
> 13 EER in California CZ 12 (Mostly cooling).
>
> Next?
>
>
> --
> Robert Wichert P.Eng. LEED AP BD&C
> +1 916 966 9060 <tel:%2B1%20916%20966%209060>
> FAX +1 916 966 9068 <tel:%2B1%20916%20966%209068>
>
>
>
>
>
>
>
> ===============================================
>
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>
>
> --
> M. Dennis Knight, P.E.
>
> Founder & CEO
>
> *W*hole *B*uilding *S*ystems, LLC
>
> P.O. Box 1845
>
> Mt. Pleasant, SC 29465
>
> Phone: 843-437-3647 <tel:843-437-3647>
>
> Email: dknight at wholebuildingsystems.com
> <mailto:dknight at wholebuildingsystems.com>
>
> Website: www.wholebuildingsystems.com
> <http://www.wholebuildingsystems.com>
>
>
>
> --
> M. Dennis Knight, P.E.
>
> Founder & CEO
>
> *W*hole *B*uilding *S*ystems, LLC
>
> P.O. Box 1845
>
> Mt. Pleasant, SC 29465
>
> Phone: 843-437-3647
>
> Email: dknight at wholebuildingsystems.com
> <mailto:dknight at wholebuildingsystems.com>
>
> Website: www.wholebuildingsystems.com
> <http://www.wholebuildingsystems.com>
>
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